Hub of a tape cassette

Abstract

A hub of a tape cassette comprising a generally circular outer ring portion (6), an inner ring portion (8) concentric with the outer portion and a generally annular rib (10) connecting the outer and inner ring portions, wherein said annular rib is formed so that its wall thickness increases continuously from a position (A) adjacent to a gate portion (G) for injection molding towards a portion (B) most apart from the gate portion, along the circumferential direction.

We claim: 
     
       1. A hub of a tape cassette, comprising: a generally circular outer ring portion,   an inner ring portion concentric with the outer portion, and   a generally annular rib connecting the outer and inner ring portions,   wherein said annular rib is formed having a tapered wall with a thickness which increases gradually and continuously from a first position adjacent to a gate portion for injection molding towards a second position most furthest from the gate portion, along the circumferential direction.   
     
     
       2. The hub of a tape cassette according to claim 1, wherein the wall thickness of the annular rib increases from the first position towards the second position at a constant rate of from 1.5 to 2 mm for every 18 mm in the length along the circumferential direction.